The objective of this project is to understand the genetic basis for the morphology and development of the mammalian skeleton. In the process, we should obtain an overview of the genetic architecture of a set of related polygenic traits in a mammal and establish the dog as a useful organism for the study of polygenic phenotypes. Our approach, involving interaction with dog owners, offers an opportunity to create a better public understanding of the research process, the role of genetics in medical research and its impact on every day life. The dog has been chosen as the animal model of choice because of its great range of morphological diversity. Recent progress on its genome has made it possible to relate genetic data on the dog genome to the genome of the human or the mouse and inbred dog populations present ideal populations in which inbreeding has concentrated many of the genes involved in polygenic disease. To determine the genetic architecture underlying the structure of the mammalian skeleton, it will be necessary to identify the multiple genes that regulate skeletal size and shape and to determine the periods during juvenile development when these genes affect growth. The results should be applicable to unraveling genetic aspects of other polygenic human diseases also found in dogs such as cancer, auto-immune disorders (such as Addison's disease), or disorders of the nervous system (such as epilepsy).